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  • Writer's pictureArt City Vets

Canine Infectious Respiratory Disease Complex (CIRDC)

Updated: Dec 1, 2023

There has been a lot of buzz on social media and the news in the last few weeks about infectious respiratory disease in dogs.

Canine Infectious Respiratory Disease Complex (CIRDC), sometimes called "Kennel Cough," is a term used to describe symptoms caused by at least a few dozen pathogens. Clinical signs may include coughing, sneezing, nasal or ocular discharge, and occasionally systemic signs like lethargy, fever, or poor appetite.

What is different right now about CIRDC?

Nothing specific. Possibly nothing out of the ordinary, but possibly something new. There is certainly a lot more media attention, but actual reports of CIRDC are pretty on par with what is normal for the last decade. CIRDC is endemic and will show up anyplace there are dogs, and while local cluster outbreaks can draw a lot of attention, they are typical for CIRDC and have been for years. For example, canine Influenza (H3N2) has been circulating actively in the eastern and western coasts for the last year or two, often popping up at shelters and dog shows.

A lot of what the media has been focusing on is typical for CIRDC, especially the inability to isolate a causative pathogen. Many of the bugs that cause CIRDC, especially influenza virus, pneumovirus, and canine respiratory coronavirus, are only detectable very early in the disease process, often requiring sampling within 4 days of clinical signs. It's extremely common (and frustrating) to not get a diagnosis with PCR or culture when sampling is done when dogs get more sick and require veterinary care. The majority of cases suspected to have “atypical CIRDC” have not had any testing at all, and those that were tested were often sampled after weeks of coughing, not within the first 4 days of symptoms. Also, many dogs have been tested using a panel that does not include pneumovirus, which could fit well with the reported symptoms.

Compared to decades ago, the number of dogs that get very sick or die has gone up, but this is likely due to the explosion of breeds at higher risk for severe disease, like French Bulldogs, English Bulldogs, Shih Tzu, Pugs, etc. Many breeds that are popular in the last 20 years are bred to have flat faces, which compromises respiratory function and increases the chance of severe disease or death from CIRDC.

At Art City, we have not noted any change from baseline CIRDC cases, and are not aware of any reported outbreaks in our region outside of the typical levels, but we will continue to monitor and provide updates to our clients when indicated.

For a good summary of recent headlines, check out the Cornell Canine Health Center and University of Florida Shelter Medicine Program updates:

What is CIRDC?

While a handful of pathogens may be transmissible to other species (such as Bordetella to rabbits, Canine Influenza Virus to cats), CIRDC is typically a disease of dogs only.

Many cases of CIRDC are caused by viruses, including Parainfluenza, Adenovirus-2, Canine Respiratory Coronavirus (different than SARS-CoV-2), Herpesvirus-1, Canine Distemper, and Pneumovirus. Multiple strains of Canine Influenza have also been identified (H3N8 and H3N2 in particular).

Bacterial pathogens can include Bordetella bronchiseptica, Mycoplasma, and Streptococcus zooepidemicus.

Similar to human cold and flu, secondary bacterial infections (such as pneumonia) are responsible for causing more severe disease, and develop usually days to weeks after the initial infection.

Also, much like human respiratory disease, dogs can also be infected with multiple pathogens at once, and not all dogs are equally susceptible or have the same clinical signs.

Most CIRDC pathogens incubate for 2-3 days, but there is wide variability. For example, influenza can start causing clinical signs within 2 days of infection, while Canine Distemper can take 6 weeks. All CIRDC pathogens start shedding prior to clinical symptoms, and most cases will have shedding and clinical signs for 5-10 days, though some can shed longer (Bordetella, Mycoplasma, influenza).

The vast majority of dogs that get CIRDC have mild, self-limiting clinical signs, and resolve with no treatment or minimal supportive care (like rest).

Dogs at higher risk of severe disease include:

-Brachycephalic breeds (squished or flat face breeds)

-Elderly dogs

-Young puppies

-Pregnant dogs

-Immunocompromised dogs (from disease or treatments like steroids or chemotherapy)

-Dogs with underlying heart or respiratory issues (such as bronchitis, heart failure, tracheal collapse, etc)

My dog is healthy. What should I do?

There is always some risk of exposure to CIRDC, just like there's always some risk that you could encounter someone shedding the flu. How cautious you should be about your dog may depend on their risk for severe illness.

Here are some basic practices for CIRDC that are similar to messaging directed at influenza control in people:

-If your dog is sick, keep it at home, ideally for 1-2 weeks after recovery.

-If your dog as been exposed to a sick dog, keep it at home

-Limit contact of your dog with other dogs. That doesn't mean zero social contact, but ideally limit the number of different dogs with which it has close interactions. Playing with the same group of dogs every day is lower risk than playing with different groups of dogs every day.

-Consider limiting access to dog-heavy areas, such as off leash dog parks, especially if there is an apparent outbreak in your area

-Consider vaccinations for pathogens like Bordetella bronchiseptica, Canine Parainfluenza Virus, Canine Adenovirus-2, and possibly Canine Influenza

My dog is healthy but higher risk for severe disease. What should I do?

Same as above, but with extra precautions. Vaccination is more important for higher risk dogs, regardless of how much contact they have with other dogs.

What should you do if your dog is sick?

The vast majority of dogs that get infectious respiratory tract disease have uneventful recovery with minimal to no medical intervention. However, severe disease can occur, especially in higher risk dogs.

If you are concerned about your dog, you should contact your vet, however a coughing dog doesn't automatically need immediate medical attention.

If a dog is very sick, deteriorating quickly, or not getting better over the course of a few days, medical attention is important. If it's just a mild upper respiratory infection, a vet visit is likely not important.

Think of respiratory infections like how they are managed in humans. If you have a mild cough and feel a bit run down, you wouldn't likely go to the doctor unless you have underlying risk factors for severe disease. The same is true for dogs. If a dog is bright and alert, eating well, and breathing normally, but has a cough and a runny nose or eyes, they don't likely need any specific treatment or testing, so a vet visit may not be very important.

Here are some clinical symptoms that should prompt a vet visit:

-Weakness, severe depression (very quiet, not engaged, just lying around)

-Loss of appetite

-Difficulty breathing (breathing faster and harder at when at rest)

-Rapid worsening of disease

-Cough that is causing significant problems such as vomiting or periods of respiratory distress

What will happen at the vet?

The first thing we assess is whether it looks like your dog is sick with infectious respiratory disease, and to see how stable your dog is. Most dogs affected with CIRDC don't need medications and will recover with rest and time.

If your dog has signs of pneumonia, x-rays and blood work may be needed, and antibiotic therapy may be recommended.

If coughing is very disruptive, then occasionally cough suppression may be helpful, though that would depend on a number of factors.

If your dog is very sick, hospitalization with intensive care, antibiotics, and oxygen therapy may be required. This is very uncommon but can happen, and when more dogs in an area are sick with CIRDC, there will be more cases that require hospitalization. If 1% of dogs require hospitalization, more dogs will need to be hospitalized if 1000 dogs are sick vs 100 dogs.

What about vaccinations?

There are dozens of known pathogens that cause CIRDC, and we can vaccinate for a few. Much like human respiratory diseases like COVID, influenza, and RSV, vaccinations do not prevent infection, but can decrease the chance of severe disease and limit the time shedding occurs.

For nearly all dogs in urban areas where face to face contact is common, Bordetella bronchiseptica and Canine Parainfluenza vaccination is important. This is usually covered in annual Kennel Cough vaccination. Mucosal vaccination (intranasal) is preferred. Some oral vaccinations that have been more commonly used over the last few years are Bordetella only, and may be part of what's driving CIRDC outbreaks of parainfluenza. Canine Parainfluenza is also in the injectable DHPP vaccine, but mucosal vaccination is far superior.

Canine Adenovirus-2 and Canine Distemper are included in the standard core DHPP vaccination (often called "Distemper vaccine"). This vaccine is typically given every 3 years to adult dogs.

Canine Influenza vaccination can be considered as well, though Canine Influenza is much more sporadic and tends to cause more isolated outbreaks than other more common CIRDC pathogens. The vaccination has also had production and backorder issues, making availability more challenging.


-Trupanion Canine Respiratory Q&A Session -

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